A disk drive, such as a magnetic disk drive, comprises a magnetic disk, spindle motor, magnetic head, and carriage assembly. The magnetic disk is disposed in a case. The spindle motor supports and rotates the disk. The magnetic head reads data from and writes data to the disk. The carriage assembly supports the head for movement relative to the disk. The carriage assembly comprises a pivotably supported arm and a suspension extending from the arm, and the magnetic head is supported on an extended end of the suspension. The head comprises a slider mounted on the suspension and a head section disposed on the slider. The head section comprises a recording element for writing and a reproduction element for reading.
Magnetic heads for perpendicular magnetic recording have recently been proposed in order to increase the recording density and capacity of a magnetic disk drive or reduce its size. In one such magnetic head, a recording head comprises a main pole configured to produce a perpendicular magnetic field, return or write/shield pole, and coil. The return pole is located on the trailing side of the main pole with a write gap therebetween and configured to close a magnetic path that leads to a magnetic disk. The coil serves to pass magnetic flux through the main pole.
As a recording pattern is recorded along tracks of the magnetic disk, recording magnetic fields leak from the opposite sides of the main pole transversely relative to the tracks. To reduce the leakage magnetic fields, a recording head is proposed in which side shields are arranged individually on the opposite sides of the main pole transversely relative to the tracks.
In the magnetic head comprising the side shields described above, erase width control is expected of the side shields. In repeating recording operation on the same track, however, recorded data may be erased or degraded in wide regions covering tens of tracks by a return magnetic field just below the side shields, in a distribution of magnetic flux that returns from the main pole to the return pole through a soft magnetic layer below a recording layer of a perpendicular recording medium.
If the side shields are spaced wide apart from the side surface of the main pole, moreover, such a phenomenon may occur that data recorded on adjacent tracks is erased or degraded by magnetic flux (or a fringe magnetic field) that is directed from a tapered portion of the main pole to the medium. Thus, the track density cannot be improved.